Abstract: In the advent of rapid agricultural development, the use of antibiotics and chemicals for pest control has been materially increased. Although effective, it invariably raises concerns about environmental pollution, drug resistance, and food safety. Aside from the high efficacy for controlling parasitic infections, the naturally occurring bioactive antiparasitic peptides are attractive for their minimal toxicity, strong selectivity, and low risk of drug resistance in applications. This article summarizes the main sources, classifications, and mechanisms of action of the highly desirable agents, and highlights the characteristics and associated neurotoxicity, membrane disruption, and immunomodulation mechanisms of the animal-, plant-, and microbe-derived peptides that displayed antiparasitic potentials. Recent studies on the plausible applications and remaining challenges are reviewed, and strategies to foster the development of new biological pesticides proposed.